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Strength Of Materials

by Jntu Heroes
Type: PracticalInstitute: JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY Downloads: 4Views: 195Uploaded: 8 months agoAdd to Favourite

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Jntu Heroes
Jntu Heroes
DEPARTMENT OF CIVIL ENGINEERING STRENGTH OF MATERIALS LAB
EXPERIMENT NO. – 01 AIM: - Study of Universal Testing Machine (U.T.M.) OBJECT: - To Study the various component parts of the Universal Testing Machine (U.T.M.) & test procedures of various practical’s to be performed. APPARATUS: - Universal Testing Machine with all attachment i.e. shears test attachment, bending attachment, tension grips, compression test attachment etc. DIAGRAM:- STRENGTH OF MATERIAL- CIVIL ENGINEERING LAB MANUAL
THEORY: - The Universal Testing Machine consists of two units. 1) Loading unit, 2) Control panel. LOADING UNIT:It consists of main hydraulic cylinder with robust base inside. The piston which moves up and down. The chain driven by electric motor which is fitted on left hand side. The screw column maintained in the base can be rotated using above arrangement of chain. Each column passes through the main nut which is fitted in the lower cross head. The lower table connected to main piston through a ball & the ball seat is joined to ensure axial loading. There is a connection between lower table and upper head assembly that moves up and down with main piston. The measurement of this assembly is carried out by number of bearings which slides over the columns. The test specimen each fixed in the job is known as ‘Jack Job’. To fix up the specimen tightly, the movement of jack job is achieved helically by handle. CONTROL PANEL:It consists of oil tank having a hydraulic oil level sight glass for checking the oil level. The pump is displacement type piston pump having free plungers those ensure for continuation of high pressure. The pump is fixed to the tank from bottom. The suction & delivery valve are fitted to the pump near tank Electric motor driven the pump is mounted on four studs which is fitted on the right side of the tank. There is an arrangement for loosing or tightening of the valve. The four valves on control panel control the oil stroke in the hydraulic system. The loading system works as described below. The return valve is close, oil delivered by the pump through the flow control valves to the cylinder & the piston goes up. Pressure starts developing & either the specimen breaks or the load having maximum value is controlled with STRENGTH OF MATERIAL- CIVIL ENGINEERING LAB MANUAL
the base dynameters consisting in a cylinder in which the piston reciprocates. The switches have upper and lower push at the control panel for the downward & upward movement of the movable head. The on & off switch provided on the control panel & the pilot lamp shows the transmission of main supply. METHOD OF TESTING:Initial Adjustment: - before testing adjust the pendulum with respect to capacity of the test i.e. 8 Tones; 10 Tones; 20 Tones; 40 Tones etc. For ex: - A specimen of 6 tones capacity gives more accurate result of 10 Tones capacity range instead of 20 Tones capacity range. These ranges of capacity are adjusted on the dial with the help of range selector knob. Engineering control weights of the pendulum are adjusted correctly. The ink should be inserted in pen holder of recording paper around the drum & the testing process is started depending upon the types of test as mentioned below. TENSION TEST:Select the proper job and complete upper and lower check adjustment. Apply some Greece to the tapered surface of specimen or groove. Then operate the upper cross head grip operation handle & grip the upper end of test specimen fully in to the groove. Keep the lower left valve in fully close position. Open the right valve & close it after lower table is slightly lifted. Adjust the lower points to zero with the help of adjusting knob. This is necessary to remove the dead weight of the lower table. Then lock the jobs in this position by operating job working handle. Then open the left control valve. The printer on dial gauge at which the specimen breaks slightly return back & corresponding load is known as breaking load & maximum load is known as the ultimate load. COMPRESSION TEST:Fix upper and lower pressure plates to the upper stationary head & lower table respectively. Place the specimen on the lower plate in order to grip. STRENGTH OF MATERIAL- CIVIL ENGINEERING LAB MANUAL

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